1. Field of the Invention
The present invention relates to wireless IC devices, and more specifically, to a wireless IC device, such as a contactless IC medium module used in, for example, an RFID (Radio Frequency Identification) system.
2. Description of the Related Art
Various wireless IC devices including a wireless IC chip and a radiation plate have been proposed.
For example, a contactless IC medium module (RFID) disclosed in Japanese Unexamined Patent Application Publication No. 2003-331246 includes, as illustrated in FIG. 7A which is a top view and FIG. 7B which is a sectional view taken along the line A-A′ in FIG. 7A, an insulating substrate 106 on which a loop antenna 102 and one electrode 101 are provided. Another electrode 103 includes a capacitor defined by electrically conductive wires 115 including insulating films. A resonant circuit including the capacitor and the loop antenna 102 is connected to an LSI 104(Large Scale Integration).
The RFID is used in a state in which the LSI, the resonant circuit, and the loop antenna are electrically connected to one another. Therefore, when a large voltage, such as a static electrical charge, is instantaneously applied to, for example, the loop antenna, the voltage is also applied to the LSI through the resonant circuit. When application of this high voltage breaks the LSI, the LSI stops functioning as an RFID module.
In order to electrically connect the individual components, all of the components must be accurately mounted on mounting electrodes. Therefore, a highly accurate mounting device is necessary, which results in an increase in the cost of the RFID.
Furthermore, when the accuracy of the mounting of the components is degraded, the module characteristics of the RFID module are also degraded.